What is the main function of thyroid hormone (T3/T4)?

The main function of thyroid hormone, specifically thyroxine (T4) and triiodothyronine (T3), is to regulate the basic metabolic rate of the body. This entails influencing how quickly the body uses energy, generates heat, and consumes oxygen. Thyroid hormones are crucial for the metabolism of carbohydrates, fats, and proteins, thus impacting overall energy expenditure and metabolic processes.

The thyroid hormones increase the metabolic rate by promoting the use of glucose and fatty acids for energy, enhancing the action of other hormones, and influencing the development and function of various tissues. This role is vital for maintaining energy balance and overall physiological health, affecting everything from body temperature regulation to growth and development.

While insulin production, milk production, and immune response regulation are important physiological processes, they are primarily controlled by other hormones and systems in the body rather than directly by thyroid hormones. For example, insulin is primarily regulated by the pancreas, and milk production is mainly influenced by prolactin. Overall, understanding the specific role of thyroid hormones in metabolism is essential for grasping their significance in maintaining homeostasis within the body.